Premium 6 Pack-- 6Pack Carbon Filters, 6Pack Filters and 6 Pack 8D Filters of premium pet fountain replacement filters for Square stainless steel water fountains. Triple Action Fountain Filter-- The pet fountain filter is composed of a cotton layer,activated carbon and an ion exchange resin.They can filter hair, heavy metals, and improve the taste of the water so that pets can drink clean and fresh water. All materials of the filter are certified by SGS. Note-- Please rinse the filter 3-5 minutes thoroughly with drinkable water before use ! Please put the flat facade upward to ensure best filtration! Easy to use-- This pet filters is easy to install,remove and replace. And we advise you to replace the filter 3-4 weeks to keep the water clean. 100% Satisfaction Warranty-- Individually packaged and sealed to maintain high quality, 30 days money back. If you have any questions, please contact us any time! We will strive to help!